fix icon paths for ST3 3014
Fix ST2 compatibility for gutter icons.
Merge pull request #1 from RazerM/FixST2

Fix ST2 compatibility for gutter icons.
Change version check to check for build 3014
Merge branch 'master' of github.com:akirk/GitGutter into akirk
DRY up that icon path biz and conform to PEP8 (lines over 80)